Plumbing Glossary

Access Valve
An access valve allows controlled entry or shutoff of water flow within plumbing systems, often used for maintenance or emergency isolation. These valves enable plumbers to perform repairs without shutting down the entire water supply. Proper identification and use are essential for efficient system management.

Angle Stop
An angle stop is a valve installed at a 90-degree angle, typically under sinks or toilets, to control water flow to a specific fixture. It provides a convenient shutoff point for repairs or replacements without disrupting supply elsewhere. Its compact design fits neatly into confined spaces.

Backflow Preventer
A backflow preventer is a device that stops contaminated water from flowing backward into the clean water supply. It protects potable water systems from pollution caused by back-siphonage or backpressure.

Ball Valve
Ball valves utilize a spherical disk to control water flow through a pipeline, offering reliable shutoff and minimal pressure loss. They only require a quarter turn to open or close fully and are common in plumbing systems.

Basin Wrench
A basin wrench is a specialized tool designed for tightening and loosening nuts in confined spaces beneath sinks. Its adjustable jaw and long handle make it essential for faucet installation and repair in tight spots.

Bathroom Vent
A bathroom vent is part of a plumbing vent system that releases sewer gases safely above a building’s roof. It helps regulate air pressure for smooth wastewater flow and prevents trap siphoning and odors.

Branch Drain
A branch drain is a lateral pipe that connects fixtures to the main drainage line, channeling wastewater from sources like sinks and toilets to the central waste system.

Check Valve
A check valve permits water flow in only one direction, preventing reverse flow within pipes and protecting systems from backflow or contamination.

Chlorination
Chlorination is the process of disinfecting water by adding chlorine or its compounds to kill bacteria and pathogens, ensuring potable water safety.

Cleanout
A cleanout is an accessible fitting within the plumbing system that allows clearing of blockages from drain pipes. Typically capped and located outside or in basements, cleanouts provide a convenient point for clearing tools.

Composite Sink
A composite sink is made from a blend of natural stone materials and resin, offering durability, stain resistance, and a modern look. These sinks are popular in kitchens for their function and appearance.

Condensate Drain
A condensate drain channels away moisture produced by air conditioning or heating systems, preventing water damage and system inefficiencies.

Continuous Loop Vent
A continuous loop vent forms a loop to maintain proper airflow and pressure in drainage systems, helping prevent trap siphoning and supporting smooth gas discharge in complex layouts.

Corrosion Inhibitor
Corrosion inhibitors are chemical agents added to water systems to reduce metal degradation in pipes and fixtures, extending the service life of components.

Coupling
A coupling is a short fitting connecting two pieces of pipe of the same diameter and type, useful for repairs and extensions.

Cross-Connection
A cross-connection occurs when potable water connects with a non-potable source, risking contamination. Devices like backflow preventers mitigate these hazards.

Dielectric Union
A dielectric union is a fitting that joins two dissimilar metals in plumbing, preventing galvanic corrosion and premature deterioration.

Dielectric Valve
A dielectric valve incorporates dielectric materials to prevent galvanic corrosion, mainly when connecting copper to steel or iron piping.

Drain Auger
A drain auger, or plumbing snake, is a flexible tool used to clear clogs within pipes by breaking up or retrieving debris, effective for stubborn blockages inaccessible by plungers.

Drainage Fixture Unit (DFU)
A Drainage Fixture Unit is a standardized measure used to estimate the load fixtures impose on a plumbing drainage system, helping size pipes appropriately.

Dry Trap
A dry trap occurs when the water seal in a trap evaporates, allowing sewer gases to enter living spaces. Proper venting and fixture use maintain trap seals.

Expansion Tank
An expansion tank accommodates increased water volume from thermal expansion in closed systems, preventing excessive pressure buildup and protecting heaters and pipes.

Fixture Branch
A fixture branch is a pipe segment connecting one or more plumbing fixtures to the main water supply or drainage system.

Float Valve
A float valve regulates water level by using a floating mechanism to open or close the valve automatically, commonly in toilets and tanks to prevent overflow.

Flushometer
A flushometer is a valve used to flush water directly from the supply pipe into toilets or urinals without a tank, providing high-pressure flushing in commercial spaces.

Gauge Pressure
Gauge pressure measures the pressure within plumbing systems relative to atmospheric pressure, crucial for diagnosing leaks, blockages, or pump operation.

Gate Valve
Gate valves use a sliding gate to fully allow or block water flow, ideal for on/off control but not for throttling. They’re durable and common in main lines.

Globe Valve
A globe valve controls fluid flow through a movable disk and stationary ring seat, offering precise flow regulation. It is preferred for throttling applications.

Grease Trap
A grease trap intercepts fats, oils, and grease before they enter the sewage system, protecting pipes from clogs and requiring regular cleaning.

Hanger
A hanger supports and secures pipes along walls, ceilings, or floors, preventing sagging and vibration.

Hard Water
Hard water contains high levels of calcium and magnesium, causing scale buildup in pipes and appliances. Water softeners are used to remediate it.

Heat Trap
A heat trap is a device or pipe configuration that reduces unwanted heat loss from hot water systems by obstructing convective heat transfer.

Hours of Operation Valve
This valve regulates water supply based on timing schedules for irrigation or industrial processes, often integrating with electronic timers.

House Drain
The house drain is the main pipe collecting wastewater from all internal drains and directing it toward the sewer or septic system.

Hydro Jetting
Hydro jetting uses high-pressure water streams to clear debris, grease, and mineral buildup inside pipes, restoring and maintaining drainage function.

Indirect Waste
Indirect waste is drainage that does not connect directly to the sewer but discharges into an air gap or receptacle, protecting potable water sources.

Kickspace Heater
A kickspace heater is a compact heating unit installed near floors, often beneath cabinets, to provide localized warmth, especially in hydronic systems.

Lead-Free Solder
Lead-free solder joins copper pipes without lead, eliminating contamination risks and meeting modern health standards.

Lift Station
A lift station is a pump system that elevates wastewater from lower to higher elevations when gravity drainage is insufficient.

Manifold
A manifold is a centralized assembly distributing water to multiple locations, allowing individual control of each branch in heating or water systems.

Mechanical Joint
A mechanical joint connects pipes using bolts and gaskets instead of solder or welding, providing flexibility and being common in heavy-duty or cast iron piping.

Meter Valve
A meter valve controls water inlet or outlet of a water meter, allowing isolation for servicing or leak detection.

Mixing Valve
A mixing valve blends hot and cold water for a desired output temperature, common in showers and faucets to prevent scalding.

Multiport Valve
A multiport valve directs water flow through several paths, often used in pool filtration for filtering, backwashing, or rinsing.

Nominal Pipe Size (NPS)
NPS is a standardized system for specifying pipe diameter, representing approximate inside diameters.

Odor Trap
An odor trap maintains a water seal in plumbing to block sewer gases, as in P-traps and S-traps.

Overflow Pipe
An overflow pipe directs excess water from fixtures to prevent flooding and property damage.

P-Trap
A P-trap is a curved drainpipe that holds a water barrier to prevent sewer gas escape and catch debris, standard beneath sinks.

PEX (Cross-linked Polyethylene)
PEX is a flexible plastic piping, resistant to scale and chlorine, favored for water supply lines in residential plumbing.

Pipe Wrench
A pipe wrench is a heavy-duty adjustable wrench designed to grip and turn pipes and pipe fittings, with serrated jaws for strong holding power.

Pressure Reducing Valve (PRV)
A PRV lowers incoming water pressure to a manageable level, protecting plumbing systems and fixtures.

Pressure Relief Valve (PRV)
This valve releases excess pressure from water heaters or boilers to prevent dangerous overpressure.

Propane Torch
A propane torch produces an intense flame for soldering copper pipes and fittings.

Reducer
A reducer connects two pipes of different diameters for seamless transitions in flow capacity.

Relief Valve
A relief valve releases water or air if pressure or temperature exceeds preset limits, commonly in water heaters and boilers.

Return Bend
A return bend is a U-shaped fitting that reverses flow direction while minimizing resistance, used in heating and drainage layouts.

Riser
A riser is a vertical pipe transporting water or waste between floors in multi-story buildings.

Sanitary Tee
A sanitary tee is a T-shaped fitting that connects horizontal to vertical drain lines, minimizing clogs and ensuring proper wastewater flow.

Sewer Ejector Pump
Removes sewage and wastewater from below-grade locations, like basements, toward the sewer or septic system.

Sillcock
An outdoor faucet or hose bib, often frost-resistant and equipped with backflow prevention.

Soldering
Joining metal pipes or fittings by melting a filler metal for a leak-proof connection, most often in copper plumbing.

Solvent Cement
Chemically bonds plastic pipes and fittings like PVC or ABS for a permanent watertight join.

Spigot
The male end of a pipe or fitting designed to fit into a corresponding female socket.

Stack Vent
A stack vent extends the main vent pipe above the roofline to release sewer gases and regulate air pressure.

Strainer
Traps debris to prevent downstream blockages in plumbing systems or fixtures, protecting pumps and appliances.

Stub-Out
A short pipe segment extending from the main system for fixture or appliance connections during installation or repairs.

Supply Line
A pipe section bringing water from the main source to individual fixtures.

Test Tee
A fitting allowing pressure or leak tests within a system by providing a dedicated access point.

Thermostatic Valve
Automatically blends hot and cold water to maintain a set temperature, enhancing comfort in showers and baths.

Thread Seal Tape
Tape (PTFE/Teflon) wrapped around pipe threads to ensure a watertight seal and prevent leaks.

Trap Arm
Connects the trap to the drain/vent in a plumbing fixture.

Trap Primer
Injects water into traps to prevent them from drying out, maintaining the water seal.

Trapper Valve
A specialized valve to maintain trap seals and prevent backflow in drainage systems.

Triple-Wythe Wall Pipe
Pipe enclosed within three wall layers, often fire-rated, requiring precise sealing and insulation.

Tub and Shower Valve
Controls water temperature and flow for bathtubs and showers, often with diverter capability.

Two-Way Valve
Regulates flow between two points, enabling shutoff or direction change.

Upflush Toilet
Uses a pump to move waste upward into drain lines, suitable for basement installations.

Vacuum Breaker
Prevents back-siphonage of contaminants by allowing air into the system under negative pressure.

Valve Box
An enclosure that houses and protects underground valves, allowing safe and easy maintenance access.

Venting Stack
A vertical pipe for air circulation and pressure regulation in drainage, extending above the roofline.

Waste Arm
Horizontal pipe leading waste from fixture traps to the drainage system.

Water Hammer Arrestor
Absorbs sudden pressure surges when valves close, preventing pipe noise and damage.

Water Meter
Measures the volume of water consumed by a property or system.

Water Pressure Gauge
Indicates system pressure, aiding in leak, blockage, or pump failure diagnosis.

Water Softener
Removes hardness minerals from water, reducing scale buildup.

Water Trap
Creates a liquid seal in drainage pipes to block sewer gases from entering occupied spaces.

Wye Fitting
A Y-shaped connector enabling angled branch connections to main drains, improving flow efficiency.

Xeriscaping Irrigation Valve
Precision valve for controlling water in drought-resistant landscaping, typically integrated with drip systems and timers.

Y-Strainer
A Y-shaped filter removing debris in piping to protect pumps, valves, and equipment.

Zone Valve
Regulates water flow to designated areas in heating or irrigation systems, enabling individual control.

Zinc Anode
A sacrificial metal rod used in water heaters and tanks to prevent corrosion by corroding in place of system metal components.